Generic molded bodies are used for example in the kitchen and bathroom, in particular as sinks, working surfaces, shower trays or the like. In these applications it is especially important that the molded bodies can be easily and thoroughly cleaned, and have high resistance to mechanical and thermal loads and especially to cyclic thermal loads in conjunction with water or water vapor.
DE 38 32 351 A1 discloses molded plastic bodies. Matched to the mass of the monomer in the binder solution, in the prior art a so-called crosslinking agent is added which causes three-dimensional crosslinking of the polymer chains among one another, and thus, increases the hardness and solvent resistance of the molded body which has been produced. The upper limit of the proportion of crosslinking agent is approximately 4% by weight relative to the amount of the monomer.
A higher proportion of the crosslinking agent, depending on the particle size of the inorganic particulate filler, leads to different results which are undesirable. If, for example, the proportion of crosslinking agent is increased when using a filler with a very small particle size, this leads to the molded bodies tearing in the course of shaping polymerization. For coarser fillers conversely an increase of the proportion of crosslinking agent leads to much more visible, in particular white regions on the surface or directly under the surface, with a distribution which is irregular, and the associated molded body does not meet the quality requirements imposed on appearance.
DE 199 49 461 A1 discloses a curable casting mass which contains 2.5% by weight of the crosslinking agent (relative to the monomer content of the binder solution) in the binder solution formed from the monomer (MMA) and polymer (PMMA). In some of the described embodiments another crosslinking agent which is different from the crosslinking agent in the binder solution is not added to the binder solution, but to a dye pigment dispersion. The molded parts produced accordingly do not have the properties which can be achieved by this invention, especially with respect to attainable smoothness of the surface and the outstanding cleanability which can be achieved thereby.
DE 195 21 638 A1 discloses a process for producing highly-filled plastics with a sparkle effect, with a filler suspension with a content of crosslinking monomers given at preferably 0.1 to 5% by weight relative to the monomer content.
JP 09 067497 A and JP 63 068655 A likewise disclose reaction mixtures which contain crosslinking agents which are not castable in the uncured state.